Method of manufacturing a fitting using a punch and die

ABSTRACT

A fitting, preferably for the assembling of a box shaped assembly, which fitting has a central panel and two or more finger portions extending from said central panel. The flange portions of each of the longitudinal edges of said finger portions being bent substantially at right angles to the associated finger portions so that each of said finger portions together with the bent flange portions form a U-shaped channel which is adapted to accomodate an edge portion of a constructional board. The bending of the flange portions being carried out by a special stamping method in such a manner that each flange portion is not only integral with the associated finger portion but is also integral with the adjacent finger portion without the corners between such adjacent bent flange portions of adjacent finger portions being torn up so that particular rigid fittings are obtained.

United States Patent Jorgensen 1 Sept. 17, 1974 [76] Inventor: Bjarne Jorgensen, Kirkebjerg Alle 6,

2720 Vanlose, Denmark [22] Filed: Mar. 29, 1972 [21] Appl. No: 239,148

[52] US. Cl 29/150, 72/375, 113/116 A, 1 13/116 Z [51] Int. Cl B23p 13/00 [58] Field of Search 72/475, 375, 414, 701, 72/411; 113/116 A, 116 Z; 29/150; 403/220, 336, 340

[56] References Cited UNITED STATES PATENTS 1,428,344 9/1922 Scouler 72/414 1,581,488 4/1926 Lewis 72/475 2,016,569 10/1935 Zinser 72/475 2,884,985 5/1959 Velecky.... 72/414 3,025,905 3/1962 Haerr 72/375 3,156,034 11/1964 Gruetjen 72/375 OTHER PUBLICATIONS Metals Handbook, 8th Edition, Vol. 4, Forming, Pgs. 23-30, 89-101, 145-154.

Primary Examiner-Charles W. Lanham Assistant Examiner-James R. Duzan Attorney, Agent. or Firm-Browne, Beveridge, DeGrandi & Kline 57] ABSTRACT A fitting, preferably for the assembling of a box shaped assembly, which fitting has a central panel and two or more finger portions extending from said central panel. The flange portions of each of the longitudinal edges of said finger portions being bent substantially at right angles to the associated finger portions so that each of said finger portions together with the bent flange portions form a U-shaped channel which is adapted to accomodate an edge portion of a constructional board. The bending of the flange portions being carried out by a special stamping method in such a manner that each flangeportion is not only integral with the associated finger portion but is also integral with the adjacent finger portion without the corners between such adjacent bent flange portions of adjacent finger portions being torn up so that particular rigid fittings are obtained.

3 Claims, 7 Drawing Figures PATENIED SEP I 71974 SHEET 1 OF 3 METHOD OF MANUFACTURING A FITTING USING A PUNCH AND DIE The invention relates to a fitting manufactured from sheet material, e.g., metal sheet, and destined for the assembling of constructional boards, e.g., chipboard.

Fittings are known which comprise a central panel and at least two finger portions projecting therefrom, which finger portions extend in the same plane as the central panel or in a plane parallel to that of the central panel and the respective longitudinal edges of which possess marginal parts which are bent at right angles and in the same direction to form flange portions, the distance between opposing flange portions corresponding to the thickness of a constructional board.

Fittings of this kind are preferably used for the construction of shelves, in which the individual constructional boards that have been constructed as shelf boards are held together by means of the fittings, which are fitted to the lateral edges which are opposed to each other at the ends of adjoining constructional boards.

In a known fitting of this kind the central panel is provided with openings, through which openings long bolts pass, at the end of which there are nuts, by means of which the fittings can be tightened against the constructional boards. The bolts engage with bent-over marginal parts of adjoining constructional boards, so that these are contiguous.

A stable shelf construction can be attained with these known fittings by employment of the said constructional boards with specially worked bent-over marginal parts, but it is disadvantageous that special boards are required which have to be manufactured with a high degree of precision and which have to be brought into engagement in a definite manner with the bolts and with each other during assembly.

It is an object of the invention to provide a fitting which renders it possible to assemble a shelf-like or boxshaped construction of high stability while using constructional boards having more or less unworked end parts or edge parts in a particularly simple manner.

According to the present invention I provide a fitting made of sheet material and adapted for connecting constructional boards, comprising a central panel, at least two finger p'ortions integral with and projecting from said central panel in the same plane as or in a plane parallel to said central part, and flange portions integral with said finger portions and disposed along opposite longitudinal edges of said finger portions, each said flange portion being integral with the adja cent flange portion on the adjacent finger portion and being integral with and bent substantially at right angles to its associated finger portion so that each finger portion and its pair of opposed flange portions together form a U-shaped channel adapted to receive snugly an edge portion of a constructional board, the mutually facing inner faces of each pair of opposed flanged portions being substantially parallel one to another and each finger portion having at least one perforation for receipt of holding means to secure the fitting to a constructional board.

Such fittings may be mounted on opposite marginal edges at the ends of adjoining constructional boards, and then subsequently secured directly to the constructional boards which preferably are constituted of chipboard, e.g., by means of screws or nails. A direct connection between the fittings, as for instance constituted by the bolts in the known construction. does not exist, nor is it necessary to have the individual boards to engage with each other, the mounting of these fittings thus being considerably more simple than that of the known fittings. Fittings designed according to the invention can be employed in conjunction with quite common constructional boards, which have merely to be cut to the dimensions desired without needing to be processed further, and which consequently permit a rapid and inexpensive manufacture. As opposed to the known fitting, the fitting according to the invention possesses the additional advantage of allowing alterations to an, already assembled construction, e.g., a set of shelves, being effected without any trouble. If, for instance, one wishes to fit an additional partition to a set of shelves, this can be built in an extremely simple manner by means of two T-shaped fittings, which can be fixed to any point desired on the edges of the con structional boards that form the shelf to be partitioned. In an analogous manner, an already existing partition can be moved to any point whatever, all that has to be done, is to remove the screws or nails securing the fittings to the constructional boards. Such a procedure is not possible with the known fittings, on account of the special constructional boards required in connection with them, that have especially worked marginal parts, which necessitate making due allowance for a possible mounting of additional partitions already during the manufacture of the boards.

It should be mentioned that a shelf construction has also become known, in which the fittings are not held together by bolts passing through. In this case, notches have been provided in the edges of the constructional boards, which engage with protruding parts of the fittings. As opposed to the fitting according to the inven tion, this known fitting necessitates additional opera tions both in the manufacture of the constructional boards as well as of the fittings. Moreover, their assembly is more difficult than when the fitting according to the invention is being utilized, and there is no possibility of installing additional partitions into an existing construction in this known construction either.

The present invention is substantially based on the recognition of the fact that it is possible, by means of simple measures, to attain a box-shaped, shelf-like construction which is considerably cheaper in its manufacture and simpler to assemble than the above-mentioned constructions. It was surprising to note that it was possible to achieve a sufficiently stable construction by means of the extremely simple measures according to the invention.

In order to stabilize the fitting, it can, if desired, have its finger portions embossed, preferably so as to form groove-shaped impressions extending in the longitudinal direction of the finger portions. These impressions, which increase the rigidity of the fitting, can be easily made, e.g., simultaneously with the bending over of the marginal parts, so that they do not increase the costs of the fitting to any appreciable degree.

The invention also relates to a box-shaped construction of constructional boards, assembled by means of fittings of the kind described above. Such a box-shaped construction comprises a plurality of constructional boards and at least one pair of fittings according to the invention, in which said constructional boards are connected together by means of said fittings, one of said pair of fittings being fitted to first edge portions of the constructional boards and the other of said pair of fittings being fitted to second edge portions opposite to first edge portions, said first and second edge portions each being received snugly in a U-shaped channel of its respective fitting in such a way that the horizontal boards are integral with each other or have their end surfaces abutting each other and each of said first and second edge portions being retained by holding means passing through a perforation in its respective fitting into the constructional board.

The invention also relates to a method for manufacturing fittings of the kind described above. In such a method use is made of a plunger member having a profile corresponding to the shape of the fitting to be manufactured and blocks cooperating with said plunger member and being arranged in a configuration corresponding to the profile of the plunger member so that said profile can be moved into the interspaces between the blocks, the blocks and the profile portion of the plunger member both having hard chrome plated surfaces and suitably rounded edges, a blank previously punched out from the sheet material being placed over the blocks and the plunger being moved against the blocks the profiled part of said plunger member being pressed into the interspaces between the blocks to the surfaces of which there has prior to the placing of the blank been applied a thin layer of lubricant, preferably a thin layer of molybdenum disulphide.

With this method the fittings can be bent in a single operation without the corners of the fittings being ruptured so that very rigid fittings are obtained which can be used for the assembling of very stable box-shaped constructions without further stiffening means being necessary.

In the following description the invention is explained in greater detail with reference to the drawings, which show by way of example some fittings according to the invention designed as shelf fittings.

In the drawings:

FIG. 1 shows a fitting according to the invention;

FIG. 2 is a sectional view along the line IIII through the fitting shown in FIG. 1;

FIG. 3 shows a fitting according to the invention, designed as a corner fitting;

FIG. 4 shows in a more detailed and perspective view the assembly of four adjoining constructional boards, held together by means of two fittings;

FIG. 5 shows a box-shaped construction in the form of a set of shelves which consists of constructional boards that are held together by means of fittings according to the invention;

FIG. 6 illustrates a method for manufacturing a fitting as shown in FIG. 1-2, and FIG. 7 illustrates a blank for use in connection with the method of FIG. 6.

In the following description the fitting according to the invention is explained only in conjunction with shelves and the utilization of the fitting in the construction of shelves, it is obvious, however, that the fitting can be employed just as well and without any modification in the assembly of other constructional boards, e.g., wall units.

The fitting according to the invention shown in FIGS. 1 and 2, which is designed as a shelf fitting, comprises a central panel 1 and four finger portions 2,3,4,5 projecting therefrom. Each of the longitudinaledges of the finger portions 2,3,4,5 has bent-over marginal parts, 2a, 2b, 3a, 3b. 4a. 4b, 5a and 5b, which are destined to accomodate the edges of shelf boards between themselves. Perforations 3l,32.33,34 are provided in each of the finger portions 2,3,4,5 of the fitting, which perforations serve to accomodate holding means, e.g., screws or nails, for the securing of the fitting on the shelf boards introduced between the bent-over marginal parts.

In the embodiment of the fitting according to the invention shown in FIGS. 1 and 2, each of the finger portions 2,3,4,5 is provided with an impression 6,7,8,9 which increases the rigidity of the respective finger portion.

FIG. 3 shows a fitting according to the invention, which is suitable for being fixed to the corner of a shelf. This corner fitting can be punched out of a sheet material, e. g., metal sheet, in one single punching operation, as can also the fitting shown in FIGS. 1 and 2.

In FIG. 4 the assembly of four adjoining shelf boards 26,27,28,29 by means of two opposed fittings according to the invention is shown in a detailed perspective view. Preferably, the shelf boards are manufactured from chipboard, which possess the advantage of being extraordinarily stable and having a highly uniform thickness. The manufacture of the shelf boards consists solely in cutting the boards to the desired size. No other operations are necessary.

In FIG. 4 are shown four adjoining shelf boards, but it will be apparent that the horizontal boards can be replaced by one through shelf board. It is only important for the strength of the construction that the vertical boards support the horizontal boards or the adjoining edge parts of two horizontal boards as shown in FIG. 4.

FIG. 5 shows a set of shelves, comprising shelf boards assembled by means of fittings according to the invention. It can be gathered from the figure that at the corners of the set of shelves, fittings of the kind shown in FIG. 3 have been employed and that on the upper, lower and lateral edges T-shaped fittings have been employed.

A method for manufacturing a fitting as shown in FIGS. 1 and 2 shall now be explained with reference to FIG. 6 which shows a tool for bending the fitting in the desired shape in a single process. The tool comprises four blocks 10,1 1,12,13 having hard chromium plated surfaces and a reciprocating shaft 14 of which the end adjacent the blocks carries a releasable plunger member 15 the under side of which has a profile with the same configuration as the fitting to be bent, i.e. in the present case a cross formed profile. This profile also has hard chromium plated surfaces.

In manufacturing a cross formed fitting as that shown in FIGS. 1 and 2 a blank 16, cf. FIG. 7, which has been previously punched out from a sheet material, is placed over the blocks 10,1 1,12,13 and then the shaft 14 with the plunger 15 is moved downwards against the blocks so that the profile on the plunger 15 is pressed into the interspaces between the blocks whereby the edge parts of the blank 16 are bent along the dotted lines in FIG. 7 at right angles to the associated finger portions to form the flange portions.

During this bending process there is a great risk that the corners l7,l8,19,20 of the blank 16 ruptured or torn up which would involve a considerable weakening of the manufactured fitting and a construction assembled by means of such fittings with torn up corners would have an insufficient rigidness.

In order to avoid such tearing up of the corners of the fitting the method according to the invention is carried out in such a way that prior to the placing of the blank 16 there is applied to the hard chromium plated surfaces of the blocks 10,1 1,12,13 a thin layer of a lubricant, preferably a thin layer of molybdenum disulphide. Furthermore the height h of the profile on the under sides of the plunger 15 is decreasing slightly, for instance one per cent, from the extremities of the plunger towards its centre. In connection with a suitable choice of the radii of curvature on the blocks -13 and on the plunger member it is then possible to bend the blank into a fitting without tearing up its corners.

If a T-shaped fitting is to be manufactured the plunger 15 with the cross formed profile is replaced by a corresponding plunger having a T-shaped profile on its under side and at the same time the interspace between the blocks 10 and 11 is filled out with a further block having the same height as the blocks 10-13. Correspondingly, by manufacturing a corner fitting as that shown in FIG. 3, a plunger having an angle shaped profile being used in connection with two further blocks filling out the interspaces e.g., between blocks 10 and 11 and between the blocks 10 and 13.

What I claim is:

l. A method for manufacturing a fitting which is made of sheet metal and adapted for connecting construction boards, said fittings including a central panel and at least two finger portions integral with and projecting from said central panel in the same plane as said central panel and at an angle with respect to each other of approximately 90, said fingers each having opposed longitudinal edge portions bent substantially at right angles to the associated finger portions and each said edge portion being integral with the adjacent edge portion of the adjacent finger portion, each finger portion and its pair of opposed edge portions forming a U- shaped channel adapted to receive snugly an edge of a construction board, said method comprising the steps of providing a die member having on its surface grooves corresponding to the U-shaped channels in the fitting to be manufactured. providing a plunger memher having protrusions facing the grooves of the die member and fitting in said grooves with a clearance corresponding closely to the thickness of the sheet material, placing a blank previously punched out from the sheet metal on the grooved surface of the die member, moving the plunger member and the die member toward each other with the blank therebetween, contacting the outer edges of the blank by the protrusions of the plunger member before any other part of the blank, bending the edge portions of the blank around a substantially inside corner to form an integrally joined corner extending at 90 from the plane of the original blank by starting the bending at the free ends of the finger portions and continuing progressively towards the central panel to prevent tearing of the integral sheet material of the blank at the corners between adjacent bent edge portions of adjacent finger portions, and continuing the relative movement between the die and the plunger members to position the protrusions of the plunger member within the grooves of the die member with the blank therebetween to permanently shape the blank to conform to the contour of the opposing surfaces of said die and plunger.

2. The method as defined in claim 1 wherein the protrusions on the face of the plunger member have a height over the plunger base which decreases slightly from the extremities of the plunger member towards the center of said plunger member whereby the step of moving said plunger and die together causes the plunger to contact the blank progressively from the outer edges inwardly.

3. The method as defined in claim 1 wherein the protrusions on the face of the plunger member have a height over the plunger base which decreases by approximately one per cent from the extremities of the plunger member towards the center of said plunger member whereby the steps of moving said plunger and die together causes the plunger to contact the blank progressively from the outer edges inwardly.

=l l= l 

1. A method for manufacturing a fitting which is made of sheet metal and adapted for connecting construction boards, said fittings including a central panel and at least two finger portions integral with and projecting from said central panel in the same plane as said central panel and at an angle with respect to each other of approximately 90*, said fingers each having opposed longitudinal edge portions bent substantially at right angles to the associated finger portions and each said edge portion being integral with the adjacent edge portion of the adjacent finger portion, each finger portion and its pair of opposed edge portions forming a U-shaped channel adapted to receive snugly an edge of a construction board, said method comprising the steps of providing a die member having on its surface grooves corresponding to the U-shaped channels in the fitting to be manufactured, providing a plunger member having protrusions facing the grooves of the die member and fitting in said grooves with a clearance corresponding closely to the thickness of the sheet material, placing a blank previously punched out from the sheet metal on the grooved surface of the die member, moving the plunger member and the die member toward each other with the blank therebetween, contacting the outer edges of the blank by the protrusions of the plunger member before any other part of the blank, bending the edge portions of the blank around a substantially 90* inside corner to form an integrally joined corner extending at 90* from the plane of the original blank by starting the bending at the free ends of the finger portions and continuing progressively towards the central panel to prevent tearing of the integral sheet material of the blank at the corners between adjacent bent edge portions of adjacent finger portions, and continuing the relative movement between the die and the plunger members to position the protrusions of the plunger member within the grooves of the die member with the blank therebetween to permanently shape the blank to conform to the contour of the opposing surfaces of said die and plunger.
 2. The method as defined in claim 1 wherein the protrusions on the face of the plunger member have a height over the plunger base which decreases slightly from the extremities of the plunger member towards the center of said plunger member whereby the step of moving said plunger and die together causes the plunger to contact the blank progressively from the outer edges inwardly.
 3. The method as defined in claim 1 wherein the protrusions on the face of the plunger member have a height over the plunger base which decreases by approximately one per cent from the extremities of the plunger member towards the center of said plunger member whereby the steps of moving said plunger and die together causes the plunger to contact the blank progressively from the outer edges inwardly. 